Restriction maps of large insert clones such as bacterial artificial chromosomes (BAC) provide relatively unambiguous markers that are easily interpretable and facilitate firstly, contig formation and secondly, sequence read alignment. We have developed a new approach to restriction mapping of BACs that can be readily automated, work with small amounts of sample and generate high resolution ordered restriction maps. The aim of this part of the project is to construct sequence ready, ordered restrict maps of chromosome 18 BAC clones derived from a contiguous 36 Mb region of human chromosome 18. We will use these maps, firstly to create a high resolution minimum tiling path from data generated by Dr. McPherson using restriction fragment fingerprinting and secondly, to crete a scaffold to reliably assemble islands of sequence data generated by D. McCombie An ordered restriction map scaffold will significantly reduce the effort required for sequence finishing. Furthermore, our maps will identify regions containing repeats which pose difficulties in sequence assembly and provide a means to verify sequence assembly. We will facilitate this with the construction of algorithms and development of software firstly for the alignment of maps to strengthen contig formation and secondly to verify sequence assembly. This will be of particular value in chromosomal regions which are difficult to assemble.